1. Field of the Invention
The present invention relates to a sheet feed roller.
2. Description of Related Art
Sheet feed rollers are used, for example, for transporting paper sheets in image forming apparatuses such as printers and facsimiles. There are two types of sheet feed rollers, i.e., a constant contact type and a non-constant contact type. A sheet feed roller of the constant contact type has a circular sectional shape, and is constantly kept in contact with a paper sheet. A sheet feed roller of the non-constant contact type has a noncircular sectional shape, and is brought into contact with a paper sheet only during the transportation of the paper sheet.
The sheet feed roller of the non-constant contact type is advantageous in that an ingredient (oil or the like) of a rubber of the sheet feed roller does not migrate to a paper sheet held in standby for transportation. In Patent Literature 1 (JP-HEI11(1999)-222323A), for example, an exemplary sheet feed roller of the non-constant contact type is disclosed, which includes a core having a semicircular sectional shape and a looped rubber belt fitted around a peripheral surface of the core.